The present invention relates to a multi-station proton beam therapy system useful in the treatment of cancer.
In 1945, R. R. Wilson proposed the use of proton beams in the treatment of cancer. {Radiology 47, 487 (1946)}. The advantage of protons in such treatment resides in the following physical characteristics
(1) the radiation dose delivered by a proton penetrating tissue rises as the proton slows down, reaching a maximum near its stopping point ("Bragg peak"), and is zero beyond the stopping point,
(2) protons in a monoenergetic beam have nearly the same range and therefore deliver a maximum dose at the same depth, and
(3) protons being relatively heavy do not deviate much from a straight line as they come to rest.
Today, proton beam therapy is in use at the Harvard Cyclotron Laboratory in association with Massachusetts General Hospital in Boston, Mass., in Japan at KKK and Chiba, and in the USSR at ITEP-Moscow, at JINR-Dubna, and at Gatchina near Leningrad. At each of these facilities, however, proton therapy uses an accelerator that was designed and built for physics research, and has now been adapted to do part-time clinical ion proton beam irradiation.
To realize the full potential of the proton beam in the treatment of cancer and other diseases responsive to radiation treatment, it is necessary for the physician to known the exact location of the site to be treated and the characteristics of the tissue overlying the treatment site. It is only with advent of new imaging techniques such as computed tomography (CT scanning) and magnetic resonance imaging (MRI) that such information is now available with the required accuracy. A full-time proton therapy facility for the treatment of cancer patients now appears to be feasible.